This invention relates generally to terminal block assemblies for electrical power distribution, and, more particularly, to filtered terminal block assemblies for removing undesirable frequencies from electronic signals.
A growing proliferation of electronic devices in modern products and systems can produce unintended and undesirable signal distortion between electrical components, systems and subsystems. While some signal distortion is tolerable in many instances, in certain applications signal distortion is a significant issue that must be controlled, if not overcome. Such applications wherein reduction and/or elimination of signal distortion is desirable include, for example, power supply systems for telecommunication systems, telecommunication switching applications, cellular base stations, radar transmission systems, industrial control systems, and instrumentation systems.
Consequently, a variety of terminal block assemblies have been introduced that include one or more filter elements coupled to electrical terminal elements for removing undesirable frequency transmission through the terminal block. One type of filtered terminal block assembly includes a tubular capacitor element mounted to a terminal stud for filtering a signal through the stud. When electrical connections are made to the terminal stud in the field, however, the tubular capacitor element may be placed under a structural load. Connections to threaded studs render this type of terminal block assembly particularly vulnerable to placing the capacitor element under stress when a wire is fastened to the stud. The resultant stress may damage the capacitor element and adversely affect filtering performance of the terminal block assembly.
In an exemplary embodiment of the invention, a terminal block assembly includes a base assembly including a terminal block housing and a terminal stud extending therethrough, a filter assembly coupled to the stud, and a ground assembly coupled to the base assembly and the filter assembly for dissipating filtered signal frequencies from signals transmitted through the terminal block. The filter assembly is mechanically isolated from the base assembly and the ground assembly to prevent structural loading of the filter assembly.
More specifically, the filter assembly includes a resilient contact member for mechanically isolating the filter assembly from the base assembly and the ground assembly. The terminal stud includes opposite ends configured for electrical connections thereto, and an undercut located between the opposite ends for retaining the resilient contact element. The filter assembly further includes a tubular capacitor element and the resilient contact member establishes an electrical connection with an inner surface of the tubular capacitor element.
Mechanical isolation of the filter element from structural load and associated stress and strain provides an operating environment of the filter element free from negative effects of structural load. Filter performance and reliability of the terminal block assembly is therefore increased in a cost effective manner.